Obstructive sleep apnoea and the need for its introduction into dental curricula.

Obstructive sleep apnoea (OSA) is a major health problem which causes blood oxygen desaturation that may initiate a cascade of events via inflammatory cytokines and adrenocorticotrophic hormone that may have impact upon quality of life and lead to potential life-threatening events. Even though OSA affects an increasing number of individuals, the role of dental practitioners in recognition, screening and management has not developed accordingly. The goal of this article was to provide updated information to dental practitioners on pathophysiology, consequences and treatment options of OSA with a focused discussion on oral appliance (OA) therapy, as this topic is not routinely included in current dental curricula of many dental schools. Additionally, we present a template dental curriculum for predoctoral and/or postdoctoral students in education regarding sleep disordered breathing.

A protection system for the JET ITER-like wall based on imaging diagnostics.

The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented.

Microleakage of IPS empress 2 inlay restorations luted with self-adhesive resin cements.

OBJECTIVE: To assess the microleakage of three self-adhesive and one etch-and-rinse resin cements when luting IPS Empress 2 (Ivoclar Vivadent, Liechtenstein) all-ceramic inlay restorations to the prepared cavities in extracted human molars. METHODS: The cylindrical Class V cavities were prepared on the buccal surfaces of 40 extracted human third molars using diamond burs. The IPS Empress 2 ceramic inlays were placed with Multilink Sprint (Ivoclar Vivadent), RelyX Unicem (3M ESPE, USA), G-Cem (GC, Japan), or Variolink II (Ivoclar Vivadent) as the control group. After storage in distilled water at 37°C for 24 hours, samples were subjected to 1000 thermal cycles between baths of 5°C and 55°C, with a dwell time of 30 seconds. The microleakage scores were examined on the occlusal and gingival margins at 30× magnification after each sample was stained with 0.5% basic fuchsin and sectioned into three parts using a thin diamond blade (Isomet, Buehler, USA) (n=40). The extent of microleakage on both occlusal and gingival margins of the restorations was scored and recorded. The microleakage data were analyzed using Kruskall-Wallis and Mann-Whitney U-tests. RESULTS: Statistically significant differences were observed between the groups in both margins according to the Kruskall-Wallis and Mann-Whitney U-tests (p<0.05). Microleakage scores on the occlusal margins were Variolink II < RelyX Unicem < G-Cem = Multilink Sprint. Microleakage scores on the gingival margins are Variolink II = RelyX Unicem < G-Cem < Multilink Sprint. CONCLUSION: Self-adhesive resin cements displayed higher microleakage scores on the occlusal margins, whereas on the gingival margins RelyX Unicem showed comparable microleakage results with the control samples.

Progress of the ITER equatorial vis/IR wide angle viewing system optical design.

The equatorial vis/IR wide angle viewing system is present in four ITER diagnostic equatorial ports. This instrument will cover a large field of view with high spatial and temporal resolutions, to provide real time temperature measurements of plasma facing components, spectral data in the visible range, information on runaway electrons, and pellet tracking. This diagnostic needs to be reliable, precise, and long lasting. Its design is driven by both the tokamak severe environment and the high performances required for machine protection. The preliminary design phase is ongoing. Paramount issues are being tackled, relative to wide spectral band optical design, material choice, and optomechanical difficulties due to the limited space available for this instrument in the ports, since many other diagnostics and services are also present. Recent progress of the diagnostic optical design and status of associated R&D are presented.

Digital analysis of mouthrinses' staining characteristics on provisional acrylic resins.

Provisional restorations are expected to be both aestethically and physically durable during the preparation of permanent restorations. In this study, the staining properties of mouthrinses containing chlorhexidine gluconate, benzydamine hydrochloride and a hybrid mouthrinse were investigated on light and dark shades of a provisional acrylic resin. Totally 80 specimens were prepared and were photographed digitally to obtain the baseline L*, a*, b* values. Each sample was immersed in test solutions for 12 h which was equivalent time to 1 year of mouthrinse use, and the post-treatment images of the test materials were acquired. All L*, a*, b* values were analysed by a graphic software, and the total colour change (DeltaE*) of each specimen was calculated. Also the same colour analyses were performed on all test solutions to establish their colour parameters. Analysis of variance and Tukey's tests were used for statistical analyses and alpha was 0.05. All test solutions produced perceptible staining on the provisional material, with DeltaE values over 3.7. In both shades, hybrid rinse caused the highest staining (DeltaE=5.705), and was followed by chlorhexidine gluconate rinse, with DeltaE value of 4.120. The third highest staining was observed with benzydamine hydrochloride rinse (DeltaE=3.959), whereas the control caused the least staining (DeltaE=3.095). The lighter shade provisional material resulted with clinically observable staining even when immersed in distilled water; however, the dark shades showed clinically perceptible staining solely with the hybrid mouthrinse. In this study, the shade of the acrylic material was the determinator of the staining process.

Comparison of digital and spectrophotometric measurements of colour shade guides.

Colour determination may be precisely performed with spectrophotometers, however this technique is time consuming and requires special devices. The aim of this study was to determine the correlation between the colour measurements performed on three shade guides of the same manufacturer, obtained with digital and spectrophotometric analyses. Sixty shade tabs of three shade guides were analysed to determine the L*, a*, b* values with a spectrophotometer. The same shade tabs were also imaged with a digital camera, and same colour parameters were determined on the digital images with the software. Three measurements for each shade tab were made with both methods. Statistical differences between the results of two methods were determined using anova (alpha = 0.05). Additionally, presence of any correlation between two methods within each guide was investigated by using correlation analysis. It was observed that the a* and b* values obtained by digital method were correlated with those of the spectrophotometer. Spectrophotometric analysis revealed no disparities among the L* measurements of the shade tabs of three shade guides (P > 0.05), but significant differences were observed between the L* values of the shade tabs with digital analysis method (P = 0.000). The digital method formed more subgroups than the spectrophotometer. For a* and b* values, both methods revealed significant differences among the shade tabs (P < 0.05). Additionally, both analyses revealed that colour characteristics of the first shade guide was different than the other two. The results obtained by digital method were correlated with those of the spectrophotometer, especially for a* and b* values.

Application of a digital technique in evaluating the reliability of shade guides.

There appears to be a need for a reliable method for quantification of tooth colour and analysis of shade. Therefore, the primary objective of this study was to show the applicability of graphic software in colour analysis and secondly to investigate the reliability of commercial shade guides produced by the same manufacturer, using this digital technique. After confirming the reliability and reproducibility of the digital method by using self-assessed coloured images, three shade guides of the same manufacturer were photographed in daylight and in studio environments with a digital camera and saved in tagged image file format (TIFF) format. Colour analysis of each photograph was performed using the Adobe Photoshop 4.0 graphic program. Luminosity, and red, green, blue (L and RGB) values of each shade tab of each shade guide were measured and the data were subjected to statistical analysis using the repeated measure Anova test. The L and RGB values of the images taken in daylight differed significantly from those of the images taken in studio environment (P < 0.05). In both environments, the luminosity and red values of the shade tabs were significantly different from each other (P < 0.05). It was concluded that, when the environmental conditions were kept constant, the Adobe Photoshop 4.0 colour analysis program could be used to analyse the colour of images. On the other hand, the results revealed that the accuracy of shade tabs widely being used in colour matching should be readdressed.

Analysis of incidence and associated factors with fractured implants: a retrospective study.

Osseointegrated threaded titanium screw-type implants rarely lose integration after the first year of clinical function. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. The purpose of the present study was to determine the incidence of implant fracture in completely edentulous and partially edentulous arches and to determine what factors may predispose an implant to a higher fracture risk. A retrospective evaluation of 4,937 implants was performed to determine the incidence of and factors common to fractured implants from a sample of implants placed and restored in one institutional setting. Based on the results of this study, the following observations were made: implants fracture at similar rates in the maxilla as in the mandible (0.6%), implant fractures occur more frequently in partially edentulous restorations (1.5%) than in restorations of completely edentulous arches (0.2%), all observed fractures occurred with commercially pure 3.75-mm-diameter threaded implants, and prosthetic or abutment screw loosening preceded implant fracture for the majority of the implants. More studies would be helpful to further explore the relationship and progression of factors associated with implant fracture.